Electric motor and/or transmission

ABSTRACT

An electric motor and/or a transmission consisting of an input shaft, an output shaft, and a case provided with a centering flange and/or a fixing flange. At least one extension sensor is allocated to the case.

BACKGROUND OF THE INVENTION

The present invention relates to an electric motor and/or a transmissionhaving an input drive shaft and an output drive shaft, and having ahousing on which a centering flange and/or an attachment flange are/isprovided.

Transmissions such as these are known and available in a very wide rangeof forms and embodiments on the market. They are used essentially forstepping up or down an input drive movement of a motor, electric motoror some other drive. Conventional known electric motors and/ortransmissions have the disadvantage that it is difficult to determinetheir life, their need for maintenance or the maintenance intervals.Furthermore, the life is greatly reduced, for example, in the event ofoverloading, which is likewise undesirable.

Since no capability to determine the life as well as the operability andload capacity of the electric motor and/or transmission is often known,it is also not possible to influence the spare parts storage, so that alarge number of spare parts must be kept in stock, which in turn resultsin undesirable stock keeping costs.

U.S. Pat. No. 4,384,493 discloses an electric motor which has acentering flange, in which case a housing of the electric motor isrotationally decoupled from the centering flange via a plurality ofbearing elements. A force measurement cell is arranged between thehousing and the centering flange.

U.S. Pat. No. 5,763,969 discloses an indicating display for an electricmotor for driving a flywheel for ventilation, in which case theindicating display has a rotation speed indication in order to indicatethe individual revolutions per minute.

U.S. Pat. No. 6,066,907 describes an electric motor having an inputdrive shaft and a housing, on which a centering flange is provided.

The present invention is based on the object of overcoming thedisadvantages mentioned above and of providing an electric motor and/ortransmission by means of which functional monitoring is possible forspecific loads and uses, for example of forces, moments, temperature,leaks, maintenance intervals etc. A further aim is to allow faster andmore reliable assembly and maintenance, with higher availability andproductivity and a longer usage capability. A further aim is to make itpossible to reduce the spare parts stockholdings. Furthermore,clarification of faults in use should likewise be possible.

SUMMARY OF THE INVENTION

With regard to the present invention, it has been found to beparticularly advantageous for the housing of an electric motor and/ortransmission to have at least one associated strain sensor, preferablyin the form of a strain gauge. It has been found to be preferable forthe strain sensor to be provided or arranged close to a centering flangein the cylindrical part of the housing. A plurality of strain sensorswhich are distributed radially around the circumference are preferablyprovided, and provide information about the actual forces and torquesthat are acting.

In this case, the intention is, for example, for an alarm signal to beswitched or to be indicated on an integrated indicating electronicsdevice if a maximum permissible torque is exceeded. If required, thecomplete installation or the manufacturing process in which, for examplea transmission such as this is being used, can also be switched off.

However, one important factor with regard to the present invention isthat the transmission data can be stored and/or indicated in theindicating electronics device or in an external evaluation unit inparticular via at least one strain sensor or else a large number offurther sensors which are associated with the electric motor and/or thetransmission, such as temperature sensors, further force sensors,rotation speed sensors or the like. In this case, these values arecompared with corresponding, stored limit values, in which case a loadstate as well as a critical or unacceptable load state of thetransmission and/or electric motor is indicated or can be indicated.

This makes it possible to check the use of the electric motor and/ortransmission during operation, so that the electric motor and/or thetransmission can be used on a power-optimized basis, while at the sametime allowing a statement to be made exactly about maintenanceintervals, life, etc.

In this way, the electric motor and/or the transmission is used only inits permissible limit and load range, considerably increasing the life.

It has also been found to be advantageous, likewise leading to anincrease in life, for at least one damping element to be insertedradially circumferentially into a casing surface in the centering flangeof the electric motor and/or transmission, in order to ensure dampingand oscillating radial bearing and centering. In this case, the dampingelement may, for example, be in the form of a radially circumferentialO-ring, which overhangs a casing surface on the outside. This islikewise intended to be covered by the scope of the present invention.This also avoids secondary force paths while likewise contributing tolonger life of the transmission and/or electric motor.

In one preferred exemplary embodiment of the present invention, thehousing of the electric motor and/or transmission is provided with anattachment flange, which is separated from the actual housing by meansof an annular incision, and in this way has a constriction in the formof an annular ring. The at least one strain sensor is arranged orassociated in the area of this constriction.

This allows the applied forces, torques etc. to be determined andestablished considerably more accurately.

The scope of the invention is intended to cover the attachment flangesurrounding the housing coaxially completely or else only at leastpartially in the form of a sleeve, with the strain sensors beingseparated from one another radially in the area of the constriction orof the constrictions.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages, features and details of the invention will becomeevident from the following description of preferred exemplaryembodiments and from the drawing, in which:

FIG. 1 shows a schematically illustrated plan view of a transmissionwith a strain sensor, an indicating electronics device and a dampingelement;

FIG. 2 shows a schematically illustrated side view of the transmissionshown in FIG. 1;

FIG. 3 shows a further view of the transmission as shown in FIG. 1; and

FIG. 4 shows a schematically illustrated longitudinal section through ahousing of an electric motor and/or transmission R.

DETAILED DESCRIPTION

As can be seen from FIG. 1, a transmission R has a housing 1, in whichan input drive shaft 3 is provided in the area of a base flange 2, whichis not illustrated in any more detail, but is only indicated here, whichtransmission R steps up or steps down a rotary movement to an outputdrive shaft 4 by means of transmission elements, epicyclic gears, planetwheel carriers, revolving planet gear mounts, etc. which are notillustrated here.

In the region of the output drive shaft 4, the transmission R has acentering flange 5. This is slightly spherical and is designed to taperoutward. There is an attachment flange 6 adjacent to the centeringflange 5, which attachment flange 6 has attachment screw holes 8 inparticular in its corner areas 7.

Two attachment screw holes 8 which are a distance from one another arepreferably formed in each corner area 7 of the attachment flange 6. Inparticular, two, three and preferably four corner areas 7 may each beprovided with arrangements of attachment screw holes 8 as the attachmentflange 6.

One important factor with regard to the present invention is that thehousing 1 has at least one associated strain sensor 9 in the cylindricalpart of the housing 1, preferably underneath the attachment flange 6.The strain sensor 9, which measures forces and torques, is preferably astrain gauge.

One important factor with regard to the present invention is theposition of the strain sensor 9 close to the attachment flange 6 on thehousing 1. However, it is also intended to be within the scope of thepresent invention for the strain sensor 9 to be associated directly withthe attachment flange 6.

However, it has been found to be particularly advantageous for thestrain sensor 9 in each case to be arranged between an arrangement ofattachment screw holes 8 and two mutually adjacent corner areas 7 on thehousing 1, close to the attachment flange 6.

This makes it possible to determine torques, force profiles, inparticular forces which are introduced into the attachment flange 6 viathe housing, allowing operating states of the transmission R to bededuced. The strain sensors 9 may be connected to an external evaluationunit 10, as is merely indicated here, or to an indicating electronicsdevice 11 in which the corresponding signals are evaluated and stored.If required, the measured values may also be stored over time in theevaluation unit 10 and/or in the indicating electronics device 11 inorder to obtain corresponding statements about the life, load states,etc.

The indicating electronics device 11, as is illustrated in FIGS. 1 to 3,is preferably fitted to the base flange 2 of the housing 1, and may alsobe in the form of an indicating display 12.

The indicating display 12 visually indicates when the transmission R hasexcessively high forces applied to it. A visual alarm can then besignaled in an appropriate form, or else an audible alarm or some otheralarm can be generated in a central monitoring facility. Furthermore,other values, such as temperature, required maintenance intervals ormaintenance times as well as lives of the transmission can also be readand evaluated on the indicating display 12. The indicating display 12can be switched manually to the respective parameters to be displayed,as desired.

One advantage with the present invention is that an optimum operatingstate is always ensured by the determination of transmission-specificparameters or electric-motor-specific parameters, such as forces,torques, temperature and possibly also the lubricant oil level.Maintenance can also be carried out on a planned basis or at theappropriate time, for example in the event of loss of lubricant. Inconsequence, all the components of the transmission are loaded onlywithin the permissible range, leading to an increase in life. Thisallows the life to be determined considerably more exactly, as isparticularly advantageous for spare parts stock-keeping. In consequence,a spare parts store can be defined and optimized exactly, for example,for a large number of transmissions that are in use. This allows smallquantities of spare parts to be stored and to be subsequentlymanufactured, or manufactured in advance, as required, also taking intoaccount predicted lead times.

In order, for example, to allow monitoring of the temperature of thetransmission, the temperature of the lubricant, the number ofrevolutions, a leakage, a filling level or the like, further appropriatesensors 13 which determine these parameters are provided within thetransmission R, in particular in the housing 1, as indicated by dashedlines in FIG. 3. These sensors 13 are likewise connected to theindicating electronics device 11 and/or to the indicating display 12 andcan be read and indicated visually. It is also feasible for these valuesto be stored over time, thus allowing the operating state to be verifiedover time, as well. This helps in particular to provide appropriateevidence, for example in the event of misuse.

In the case of the present invention, it has also been found to beadvantageous, as is indicated clearly in particular in FIGS. 2 and 3,for at least one radially circumferential damping element 14 to beprovided in an at least partially circumferential groove 16 in the areaof the centering flange 5, between the attachment flange 6 and theoutput drive shaft 4, which preferably tapers in the outward directionand is slightly spherical. It is also important for the presentinvention for the damping element 14, which is inserted radiallycircumferentially into a casing surface of the centering flange 5, to bein the form of an elastically deformable element. The damping element 14is preferably in the form of a rubber element, and clasps the surface ofthe centering flange 5.

An O-ring 17 is preferably inserted into the circumferential groove 16as the damping element 14.

If the centering flange 5 of the transmission R is inserted into anappropriate, matching holding flange, then the transmission R is mountedfloating and exactly centrally by means of the damping element 14 in aholding flange that is not illustrated here. The important factor is afloating bearing, so that no secondary force paths can be created. Inthis case, it is likewise intended to be within the scope of the presentinvention for, for example, a plurality of radially circumferentialgrooves 16, which are arranged parallel to one another, to be providedexternally in the centering flange 5, in order to provide a plurality ofdamping elements 14 and/or O-rings 17 radially on the centering flange5.

In comparison to conventional centering flanges, the centering flange 5in the case of the present invention has play with respect to a holdingflange which is not illustrated, so that the damping elements 14, whichproject outward beyond the centering flange 5, form a floating bearing.

In particular, it is intended to be within the scope of the presentinvention for the transmission to be in the form of an electric motor ora unit comprising an electric motor and transmission.

In one preferred exemplary embodiment of the present invention, as shownin FIG. 4, a housing 1 of an electric motor and/or transmission R isindicated, although only a cross-sectional area of the housing 1 isindicated. On the outside, this is adjacent to an attachment flange 6,which is separated from a casing surface 20 of the housing 1 via anincision 18.

A constriction 19, which is used to accommodate at least one strainsensor 9, is formed in the area of the incision 18 in the attachmentflange 6.

A plurality of strain sensors 9 which are arranged separated from oneanother radially around the circumferential constriction 19 or aroundthe attachment flange 6 are preferably arranged or provided.

Furthermore, the attachment flange 6 has a plurality of attachment screwholes 8, as are also indicated by way of example in FIG. 1. However, itis preferable for the attachment flange 6 to at least partially orcompletely coaxially surround the housing 1 or the casing surface 20 inan annular form, and for the incision 18 likewise to be formed, like asleeve, from the attachment flange 6 itself, between the casing surface20 of the housing 1.

The radially circumferential constriction 19, in particular, allowsexact sensitive determination of the resulting forces, torques etc., inthis area, via the strain sensor 9. This has been found to beadvantageous in the case of the present invention.

1. Transmission comprising a driveshaft (3), an output shaft (4) and ahousing (1) including a centering flange (5) and an attachment flange(6), the housing (1) is provided with at least one electronic displaysystem (11), wherein the electronic display system (11) is connected toa plurality of sensors (13) distributed radially around the housingcomprising strain sensors, force sensors, temperature sensors and,incremental sensor, assigned to a transmission, permissible values andlimiting values such as force, temperature, service life, number ofrevolutions are visually displayed and read off on the electronicdisplay system (11) wherein the values which are generated in theelectronic display system (11), are transmitted in a wireless fashion toan external evaluation device (10), wherein the housing is provided witha radially circumferential constriction (19) and a plurality of thestrain sensors are arranged separated from one another radially aroundthe circumferential constriction.
 2. Transmission according to claim 1,wherein the centering flange (5) has at least one radiallycircumferential groove (15) in which at least one damping element (14)is located.
 3. Transmission according to claim 1, wherein the pluralityof strain sensors (9) are distributed radially around the attachmentflange (6) in the region of the housing (1), opposite the centeringflange (5).
 4. Transmission according to claim 1, wherein the attachmentflange (6) is spaced apart coaxially from an outer casing (20) of thehousing (1) by a radial indent (18).
 5. Transmission according to claim4, wherein the attachment flange (6) is provided with the radiallycircumferential constriction (19) proximate to the indent (18) and atleast one strain sensor (9) is accommodated in the constriction (19). 6.Transmission according to claim 4, wherein a damping element (14) isinserted into the radial indent (18) and comprises an elasticallydeformable rubber element.
 7. Transmission according to claim 6, whereinthe damping element (14) comprises an O ring (17).
 8. Transmissionaccording to claim 7, wherein a plurality of circumferential grooves(16), which are spaced apart from one another and parallel to eachother, are provided on the centering flange (5) and each is providedwith a damping element (14).
 9. Transmission according to claim 6,wherein the damping element (14) projects outward beyond an outer casingof the centering flange (5).
 10. Transmission according to claim 1,wherein at least one strain sensor (9) comprises a strain gaugeconnected to an evaluation unit (10) and an electronic display system(11).
 11. Transmission according to claim 10, wherein radial forces aredetermined with the at least one strain sensor (9) and when a predefinedlimiting value is exceeded, a signal is generated and displayed in theelectronic display system (11).
 12. Transmission according to claim 11,wherein the signals which are generated by the at least one strainsensor (9) are recorded over time, stored in the evaluation unit (10)and, saved in the electronic display system (11).
 13. Transmissionaccording to claim 12, wherein the at least one electronic displaysystem (11) is assigned to a base flange (2) of the housing (1). 14.Transmission according to claim 11, wherein transmission-specific dataincluding force, temperature, transit time, and number of revolutions isdisplayed by the display unit (12).
 15. Transmission comprising adriveshaft (3), an output shaft (4) and a housing (1) including acentering flange (5) and an attachment flange (6), the housing (1) isprovided with a plurality of strain sensors (9), wherein the housing (1)is provided with a radially circumferential constriction (19) near tothe attachment flange (6) and a plurality of the strain sensors (9) arearranged in the circumferential constriction (19) and are attached tothe housing in the circumferential constriction (19) for measuringforces and torques acting on the transmission housing (1). 16.Transmission according to claim 15, wherein the attachment flange (6) isspaced apart coaxially from an outer casing (20) of the housing (1) by aradial indent (18).
 17. Transmission according to claim 16, wherein theattachment flange (6) is provided with the radially circumferentialconstriction (19) proximate to the indent (18) and at least one strainsensor (9) is accommodated in the constriction (19).
 18. Transmissionaccording to claim 16, wherein a damping element (14) is inserted intothe radial indent (18) and comprises an elastically deformable rubberelement.
 19. Transmission according to claim 18, wherein the dampingelement (14) comprises an O ring (17).
 20. Transmission according toclaim 15, wherein at least one strain sensor (9) comprises a straingauge connected to an evaluation unit (10) and an electronic displaysystem (11).
 21. Transmission according to claim 20, wherein radialforces are determined with the strain sensors (9) and when a predefinedlimiting value is exceeded, a signal is generated and displayed in anelectronic display system (11).
 22. Transmission according to claim 21,wherein the signals which are generated by the at least one strainsensor (9) are recorded over time, stored in an evaluation unit (10)and, saved in the electronic display system (11).
 23. Transmissionaccording to claim 22, wherein the at least one electronic displaysystem (11) is assigned to a base flange (2) of the housing (1).